Acoustical apparatus



194% P. "r. RUSSELL 2,395,722

ACOUSTICAL APPARATUS Filed Dec. 9. 1936 3 Sheets-Sheet l INV ENTOR PHILIP T. RUSSELL ATTORNEY 19, 1946. uss L| 2,396,722

I ACOUSTICAL APPARATUS Filed Dec. 9, 1936 3 Sheets-Sheet 2 INVENTOR PHILIP T. RUSSELL k BY ELLE-E. ATTORNEY arch 19, 146.

P. T. RUSSELL ACOUSTI CAL APPARATUS Filed Dec. 9, 1936 5 Sheets-Sheet 3 lNVENTOR PHILIP T. RUSSELL ATTORNEY Patented Mar. 19, 1946 ien'rsnr (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 4d Qlaims.

My invention relates to acoustical apparatus and more particularly to such an apparatus wherein the acoustical instrumentality for receiving and/or transmitting sound energy is mounted for efiective translatory and/or rotational movement to thus enable the extension, retraction or rotation of said instrumentality to desired points within a fluid medium, the movements of said instrumentality being remotely controlled from stations which are advantageously located and the rotational and transiatory positions of the instrumentality beingremotelyindi- V cated at these stations.

Subaqueous acoustical apparatus heretofore known and installed for use on either naval or commercial vessels has been wholly inadequate in that it has been cumbersome in construction, lacked flexibility and speed of movement, and, insofa as I am aware, has never been susceptible oi remote control. It is of course essential that through the cover of a sea chest and is movable withrespect thereto while maintaining the fluidtight integrity thereof. The acoustical instrumentality is preferably, although not necessarily, of an electro-mechanical type and as such is capable of directively transmitting and/or receiving a supersonic beam of high frequency sound energy. When in use the acoustical instrumentality is positioned entirely below the keel of the vessel and when not so employed can .be raised until it is housed in the aforementioned sea chest within the vessel to thus protect the instrumentality and prevent its offering any parasitic resistance to the vessel's movement.

For imparting translatory and rotary movement to the acoustical instrumentality I employ among other things a plurality of electric motors mechanlcally coupled to the vertical supporting shaft, the energization, speed and direction of rotation of which is controlled by an electrical system or circuit operable from stations located remotely at advantageous positions on the Vessel.

' Limit switches of any suitable construction are properly associated with the electrical system and the movable parts of the apparatus so as to automatically limit the translatory and rotational movement of the acoustical instrumentality. Means are also provided for indicating at a remote point the position of the acoustical instrumentality in its translatory path of movement as well as its relative rotational position with respect to the vessel.

With the apparatus of my invention I attain a flexibility and speed of movement of the acoustical instrumentality hitherto unknown to the prior art and all of which is accomplished by remote control. Thus with my apparatus I am enabled to hoist or lower the acoustical instrumentality at a speed at least as great as 3 inches per second and rotate the same in azimuth at speeds of One or four revolutions per minute or more if desired. The operations of hoisting and lowering the acoustical instrumentality are possible of accomplishment when the vessels speed i thirty-five lmots o less and rotation thereof is feasible with the instrumentality in its extended position when the speed of the vessel is thirty-five knots or less. My acoustical apparatus operates satisfactorily in all respects even though the vessel is rolling or pitching in a heavy seaway and its operation is in no wise impaired when the apparatus is inclined at an angle of 45 to its normal position by this rolling or pitching. It is thus seen that I provide an acoustical apparatus which is eminently suited for facilitating and safeguarding navigation during fog or other conditions of low visibility and for determining the direction and distance of aids or obstructions to navigation. Furthermore, my apparatus is of great strategic and tactical value to commanders of naval vessels since its use permits not only the effective detection of a hostile vessel within the theater of operations but also the ascertainment of its direction and distance.

In the light of the foregoing, it is an object oi. my invention to provide an acoustical apparatus wherein the acoustical instrumentality for receiving and/or transmitting sound energy is mounted for effective translatory and/or rotational movement to thus insure flexibility and speed of movement of the said instrumentality under all operating conditions.

It is another object of my invention to provide an acoustical apparatus wherein the acoustical instrumentality for receiving and/ or transmitting sound energy is mounted for effective translatory movement and wherein the means for imparting movement to the instrumentality is rendered inoperative upon the completion of. a predetermined movement of translation by the ins strumentality.

It is another and further object of my invention to provide an acoustical apparatus wherein the acoustical instrumentality for receiving and/or transmitting sound energy is mounted for transmitting sound energy is mounted for effective translatory and rotational movement and wherein the means for imparting movement to the instrue mentality is rendered inoperative upon the completion of predetermined movements of translation and rotation by the instrumentality.

It is another and further object of my invention to provide an acoustical apparatus wherein the acoustical instrumentality for receiving and/or transmitting sound energy is mounted for eflective translatory and/or rotational movement and wherein means are provided for remotely indicating the position of the instrumentality in its translatory and/or rotational paths of movement.

It is another and further object of my invention to provide an acoustical apparatus wherein the acoustical instrumentality for receiving and/ or transmitting sound energy is mounted for effective translatory and rotational movement andwherein the means for imparting rotational movement to the instrumentality is operable to accomplish its intended function only'upon the completion of a predetermined movement of translation by the instrumentality.

It is another and further object of my invention to provide an acoustical apparatus wherein the acoustical apparatus taken on the line 3--3 of Fig. 2; and

Fig." 4 shows schematically the control circuit for the electric motors which are designed to effect movements of the acoustical instrumentality.

Turning now to Figs. 1, 2 and 3 of the drawings, there is shown depicted therein at I a sea chest to the flange 2 of which the sea chest cover 3 is bolted or secured in any other suitable manner. A tube or shaft 4 extends through the bearing 5 in the sea chest cover and has mounted at one end thereof an acoustical instrumentality 6 for transmitting and/or receiving sound energy, the said instrumentality being preferably, although not necessarily, of an electro-mechanical type; The remaining end of the tube or shaft 4 is rotatably mounted on a travelling yoke or support 'I in a manner to be described more particularly hereinafter. Four vertical structural members 8, 9,

l0 and II serve to support a motor assembly and I are bolted to the sea chest cover 3 at their lower ends and to the top platform or motor base casting l2 at their upper ends. Two additional vertical structural members I3 and I4 similarly secured provide guides for the travelling yoke or support I in its translatory paths of movement.

For hoisting and lowering the yoke or support 1 there is provided an electric motor l5 of suitable design and rating which is connected by means of a coupling lliand a shaft," to a worm reduction gearing within a housing is. A hoisting and lowering pinion I9 is driven directly from the reduction gearing within the housing l8 and meshes with the hoisting and lowering gear 20 keyed to the cross shaft 2|. Pillow blocks 22 and 23 equipped with self-aligning bearings, one of which is shown at 24,-suppor't the cross shaft 2| on which are rigidly mounted two sprockets 25 and 26 for I driving the hoisting and lowering chains 21 and 28.

acoustical instrumentality for receiving and/or transmitting sound energy is mounted for eflective translatory and rotational movement and wherein the means for impart translatory movement to the instrumentality is operable to accomplish its intended function only when the said instrumentality has attained a predetermined angular.

position.

It is another and still further object of my invention to provide an acoustical apparatus wherein the acoustical instrumentality for receiving and/or transmitting sound energy is mounted for effective translatoryand rotational movement and wherein a travelling bearing is provided to insure unrestricted rotation of'the instrumentality when it is in its extended andoperative position.

These and other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference'to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a view in partial cross-sectional elevation showing the manner of mounting the acoustical instrumentality for effective translatory and/ or rotational movement as well as all appurtenant parts and mechanisms essential for effectuating the desired movement, the view being broken near its middle portion so as to make possible a complete showing of the acoustical apparatus:

Fi 21s a view in sideelevation of my acoustiapparatus as seen fi'om'a positlonto o Fi 3 isa plan view of certain parts of my Yokes 29 and 30 are adjustabiy secured to the seachest cover 3 androtata-bly support the idler sprockets 3| and 32 which likewise mesh with the chains 21 and 28 respectively. The chains 21 and 28, as shown, are connected at their adjacent ends to the yoke or support 1 by means of adjustable connections 33 and 34 provided for this purpose. Furthermore, the chains are adjusted so that they will be loose enough to run freely and yet tight enough so that any inclination of the apparatus caused by list or pitch of the vessel will prevent their striking against adjacent parts thereof. About one inch above the upward limit of travel of the yoke or support I there are bolted to'the structural guide members l3 and I4 rubber bumpers or equivalent shock absorbers 35 and 36. Similar'shock absorbers not shown are mounted about one inch below the lower limit of travel of the yoke and secured to the structural guide members energized to rotate in a direction such that the acoustical instrumentality 6 will be moved from its housed position within the seachest to its extended and ol a 'ativeposition, power will be transmitted through .the coupling l6, shaft ll, reduction gearing the housing 18, hoisting andlowerins pinion I9, and hoisting and lowering gear 20 to the cross shaft 2| to cause rotation of the same.

The chains 21 and 28 meshing with their respecvessel at the apparatus.

aaoavaa tive sprockets and secured to the yoke or support i insure movement of the shaft 4 with the acoustical instrumentality 6 to the desired position. Upon the completion of the desired movement, the energization of the motor I5 is automatically interrupted in a manner which will be pointed out more in detail hereinafter. If now the motor 55 is energized but in such a manner as to cause a direction of rotation thereof which is opposite to that previously assumed it is evident that the acoustical instrumentaiity 6 will be retracted from its extended and operative position to a housed position within the seachest, the energization of the motor being again automatically interrupted upon reaching the latter position.

Within a cavity of the yoke I there is contained a roller bearing'til which" supports the weight of the tube or shaft 4 and its component parts. The upper race of the bearing fits into a casting as which as shown is screw-threaded into engagement with the upper end of the shaft 4 and there locked in position by a set screw Mi or other suitable means. A training gear 4| for rotating or training the shaft d is rigidly secured thereto in any suitable manner. A dial t2 graduated in degrees from to 360 is adjustably attached to the gear M for cooperation with the pointer 43 to indicate the angle of train or relative bearing of the acoustical instrumentality with respect to the The dial is adjustably mounted on the gear it so that any arbitrary position of the acoustical instrumentality 6 may be taken as the zero angle of train or point from which initial excursions of rotation are made. The adjustable dial may, if desired, be positioned with its zero graduation opposite the pointer t3 when the sound active face of the acoustical instrumentality is facing forward and making an angle of 90 with the keel of the vessel.. Any other adjustment of these parts, however, may be made as desired. A suitable bearing it within the yoke i supports a trainingpinion 65 which meshes with and drives the training gear M. The machined grooves 56 and M in the yoke I which accommodate the vertical structural guides 13 and M respectively prevent rotation of the yoke thereby insuring effective communication of the torque delivered by the training pinion 45 to the training gear M with ensuing rotation of the tube or shaft 5. A training shaft 68 is provided with two keyways db running the full length of the path requisite for hoisting" and lowering the acoustical instrumentality, this shaft as shown being splined to the training pinion A5 in all positions of adjustment of the latter. At its lower end the shaft 63 is supported by a suitable bearing 50 positioned v within the sea chest cover and at its upper end is connected by means of a flexible coupling 5i to a worm wheel reduction gearing within the housing 52. A plural speed electric motor 53 of suitable design and rating for rotating the shaft 4 is connected by means of a coupling 56 to the reduction gearing within the housing 52 and like the hoisting and lowering motor i5 is provided with a pulley 55 for hand operation. The manner of rotating the shaft d and its attached acoustical instrumentality 6 is believed to be apparent. Assuming that it is desired to rotate the shaft 5 in a clockwise or right-handed direction as viewed from theupper side of the yoke i, the motor 53 is energized to give the desired direction of rotation of the shaft *3 and power is transmitted therefrom through the reduction gearing within the housing 52, coupling 58 and shaft it to the training pinion 45. Since the training pinion 55 at all times meshes with the training gear M, it is evident that the shaft 4' can be trained to any desired angular position so long as the motor 53 is ener- 5 gized. For reasons that will be set forth at greater length hereinafter, it is desirable under certain circumstances to limit the angle of train of the acoustical instrumentality in both of its directions of rotation, the manner of accomplishing which will likewise be explained subsequently.

On the casting 39 there is fixedly mounted a terminal casting 56 with a terminal tube 5'! for accommodating the electrical wiring which extends from the cable 58 through the shaft 4 to the elec- 1 tro-mechanicai, acoustical instrumentality 6. The terminal casting 56 supports at its upper end an annular switch 59, the function of which will be pointed out more in detail hereinafter, and at its lower end a gear 50 which meshes with and a gear 6| of a synchronous transmitter 62.

The transmitter is supported by a metallic casting 53 which is bolted to the yoke or support 'i.

A cable 66 connects the synchronous transmitter 62 to asynchronous receiver 65 positioned at a remote and advantageous position on the vessel from which the apparatus as a whole may be controlled, the receiver serving to indicate the position or angle of train of the acoustical instrumentality. It is thus seen-that the arrangement of the parts of my apparatus makes possible a direct observation of the angle of train or relative bearing of the acoustical apparatus at the apparatus by means of the dial t2 and pointer 63, as well as at a remote station through the synchronous transmitter 52 and receiver 65 which are adjusted to duplicate or repeat the readings of the dial and pointer.

The tube or shaft t is hollow bored and of a metal which will resist corrosion. A flange 36 4o threaded and welded to the lower end of the shaft; 6 is engaged by and secured to a complemental flange 67 of the acoustical instrumentality 6 to thus support the same. The extreme ends of the tube have a somewhat larger inner diameter than the remaining portion to thus accommodate rubber and metal, or sandwich packing seals at these points. These seals provide supports for the connecting wires passing through the tube to the acoustical instrumentality s and also support means for removing from the internal parts of the tube any water that may collect there by reason of condensa- -tion. The upper seal includes top and bottom metallic plates 58 and 69 between which there is interposed a rubber section iii. Both top and bottom plates are drilled for entering wires, an air valve, an evacuating conduit ii and for tightening bolts, one of which is shown in posi-, tion at E2. Tightening of the bolts causes com- 0 pression of the centerrubber section Hi thus forming an air-tight joint with the inner wall surface of the tube 6. Compression of this center section iii also forms a fluid impervious seal between it and the various elements which pass therethrough. The seal it at the bottom of the shaft 3 is similar in construction and function and is provided with a passageway M at its center to insure the entrance of air to the space beneath, whereby any accumulated fiuid is 70 caused to pass upwardly through the conduit ii. This conduit is capped at the point where it passes through the top of the upper seal and extends downwardly through the tube d and lower seal it to a point in line with the bottom 7 5 of the flange 65. Air introduced under pressure the flange 66.

through the air valve (not shown in the drawings) in the top seal will cause an accumulated fluid up to the level of the bottom flange 68 to be expelled through the conduit 1! when its cap is removed.

When the acoustical instrumentality is extended and subjected to the fluid pressure while the vessel is underway, it is essential that apoint of support be provided as close to the center of this pressure as possible. In order to provide this additional support there is shown a travelling bearing which moves within the sea chest on vertical strips I6 and H, the said bearing having bolted within its body a lignum vitae bearing identified in general by the reference character 18 in which the tube 4 slides and rotates. The lignum vitae segments, one of which is shown at 19, are fitted in accurately dove-tailed slots of the bushing 80, a holding ring 8| threadedly engaging the bushing to thus prevent vertical movement of the lignum vitae segments. .In the manufacture of these bearings the lignum vitae segments are inserted in the dove-tailed slots of the bushing, soaked in water and then bored to a diameter which provides suificient clearance for movement of the shaft 4. Soaking the lignum vitae segments in water simulates the swelling of the wood attending the use of the bearing under actual service conditions and thus insures a proper fit. Downward movement of the travelling bearing is limited by'a stop (not shown in the drawings) forming part of the sea chest. When the shaft is hoisted the bottom flange 66 strikes the travelling bearing in its upward movement and carries the bearing to its normal housed position within sea chest with the bearing at rest on When the shaft is lowered for use, the traveling hearing will tend to dro of its own weight. debris may prevent this as will also the pressure of the water with the vessel underway when the acoustical instrumentality emerges beyond the opening in the sea chest. It therefore becomes necessary to provide means for forcing the travelling bearing to its correct position when the acoustical instrumentality is to be projected for use. For accomplishing this I provide a split pushdown clamp 32 which tightly grips the tube t and forces the travelling bearing downwardly during the projection of the shaft t thus insuring that thebearing will locate itself approximately at its extreme outward position and. thereby provide the requisite support for the tube.

Where, however, the sea chest 'is relatively shallow a clamp as shown at 82 cannot be convenientl'y employed. In order to insure that under these circumstances the travelling bearing will reach its proper position during the projection of the shaft 43 I have adopted an alternative scheme wherein the pressure exerted by However, accumulation 'of sea.

compressed to insure a watertight joint and yet permit movement of the tube 4 without excessive friction. The purpose of this valve is to provide.

a convenient means for closing the opening in the sea chest cover should the shaft or tube 4 be either removed orcarried away. A handle 85 for operating the valve is shown in a position to open the same.

For limiting the movements of the acoustical instrumentaiity G in its various excursions of translation and rotation, I provide limit switches which may be constructed in any of several forms.

Thus, for example, trigger switches actuatedby tracted or extended position is identified in general by the reference character to. Within the housing 8'] of the switch there are mounted two screw threaded shafts 88 and 39 carrying the travelling hexagonal nuts 90, 9|, 92 and 93 which are held against rotation by the cover plate of the housing, the rotation of the shafts being controlled by the pinions 9d, 95 and gear 96 which is directly connected to the reduction gearing within the housing i8 as is thehoisting pinion Hi. The nuts at, 94, 92 and 93 control their'respective toggle switches at, all, as and 00 which are incorporated in and form part of the control circuits of the control system to be described hereinafter. The upper nuts 90, 9!, and their respective toggle switches 91, 98, serve to control the indicating lights which advise the operator of the position of the acoustical instrumentality; and the lower nuts 92 and 93 with their respective toggle switches 99 and 00 limit the excursions of the acoustical instrumentality in its translatory paths of movement. The manner in which this limit switch operates is believed to be clear.

Since each of the hexagonal nuts is held against rotation bythe cover plate of the housing 81 which bears against one of its sides, the nut will travel along the screw threaded shaft when the shaft is set in motion. At a specified point the toggle switch controlled by this particular nut will be tripped,-thereby producing the required control by opening or closing the proper auxiliary circuit. Since the screw threaded shafts 88 incl 89 are driven from the reduction gearing within the housing i8 which also drives the cross shaft 2! for hoisting and lowering the acoustical instruthe yoke i is used against the tops of pushrods secured to the travelling bearing. These rods pass through suitable stufiflng boxes within the sea. chest cover. Upward movement of the travelling bearing in this alternative embodiment is produced by the flange 66 striking the bearing.

mentality, it is evident that any desired, automatic and complete control of the acoustical instrumentality may be obtained by proper initial adjustment of the travelling nuts along their respective shafts.

A limit switch of the travelling nut type for restricting the rotation of the shaft i to any denumber of revolutions in either direction to thus prevent injury to the cable 58 by excessive rotation of the shaft is identified in the drawings by" the reference character Hill. The screw threaded shaft I02 of this switch is driven by the bevel gears i 63, 604 from the same reduction gearing within the housing 52 that drives the training shaft 8. The travelling nuts I05, I which are movable along the shaft I02 control their respective toggle switches IIJ'I, Hi8, which are incorporated in proper relay circuits of the control system to be described hereinafter. Since this limit switch in other respects is identical with switch 86 no further description thereof is deemed necessary.

A connection box N19 is provided with suitable terminals for the necessary ships connections and with wire connections to the hoisting and lowering, light indicating and training limit switches. It is to be emphasized at this point that the motor platform. l2 need not be supported from the sea chest cover 3 in the manner shown in the drawings since it might be equally well supported from any part of the ships frame as de. sired. Furthermore, it is not essential that the sea chest have a cylindrical shape. Its crosssectional area may under some circumstances be rectangular in contour where the construction of the vessel in which it is installed so requires.

The electrical system for controlling the hoisting or lowering and training motors is shown schematically in Fig. 4 of the drawings wherein Illla, Ildb, lllic designate the 3-phase mains which serve to supply the alternating current. The hoisting and lowering motor I5, which is of a 3-phase, squirrel cageinduction type, is adapted for connection to the current mains by means of the magnetically operated three-pole doublethrow switch Hi. This switch includes two sets of stationary contacts identified by the reference characters l 32h and l l3-Z respectively which are adapted to be selectively engaged by the movable contacts lid. These latter contacts are normally spring biased to a position midway between the stationary contacts and are simultaneously moved into engagement with either set of stationary contacts by the armature H5 and the solenoids II 5 and i ll cooperating therewith. Thus when the solenoid H6 is energized the movable contacts H4 will engage the stationary contacts IlZh withthe result that the motor ill will be energized in such a direction as to cause a hoisting or raising of the acoustical instrumentality 6. Conversely, energization of the solenoid ill results in an engagement of the movable contacts H4 with the stationary contacts BIB-1 with attendant reversal of phase rotation in the motor l5 and hence reversal in'its direction of rotation, thus causing a lowering of the acoustical instrumentality d.

The training motor 53 is a 3-phase. squirrel cage induction type provided with separate highspeed and low speed windings, its connection to the 3-phase current mains Illla, II 011, M00 being effected by the magnetically operated 3-pole double-throw switches H8 and H9. The switch I as is identical in construction and operation with the switch ill previously described and includes two sets of stationary contacts I201, I2I--Z adapted to be selectively engaged by the movable contacts lZZ which are normally spring biased to a position midway therebetween and controlled in their movements by the armature I23 cooperating with solenoids ltd and E25. The sole function of the switch I i8 is to insure the connection of the desired winding of the motor 53 in circuit and for accomplishing this purpose includes two sets of stationary contacts I26 ms adapted to be selectively engaged by movable contacts I23 controlled by the armature I29 and cooperating solenoids I343, I3I. Since the switch II9 controls push-button switch the starting and stopping of the motor 53 as well as its direction of rotation and the switch I I8 insures the connection of the desired winding in circuit, it is evident that complete speed and directional control of the'lnotor 53 is had.

The limit switch 88 is shown schematically with the screw-threaded shaft 88, the travelling nuts 99, SI and the toggle switches 91, 98 controlled respectively thereby. The toggle switch 98 when bridging its stationary contacts completes a circuit through an electric lamp I32G located at the remote control panel for indicating when the acoustical instrumentality 6 is housed. Electric lamp I33R similarly located is employed for advising the operator when the acoustical instrumentality has substantially reached its extended or most outward position, the energization of this lamp being controlled by the toggle switch 91 and its cooperating stationary contacts. In the lower portion or the limit switch there are shown schematically the screw-threaded shaft 89, the travelling nuts 92, 93 and the toggle switches 99 and W9 controlled respectively thereby. The switch we serves to control the relay circuit which includes the solenoid M8 and the switch 99, the relay circuit which includes the solenoid ll'i.

A two element push-button station I35 which may be remotely positioned is provided for controlling the energization of the solenoids H6, ill of the switch l it and includes a spring biased I35L for controlling the downward movement of the acoustical instrumentality and a spring biased push-button switch IttI-I for controlling the hoisting or upward movement thereof. The switches 9361- and E3811 include upper and lower movable contacts I35, Hi5" and @385, I36" respectively, the lower movable contacts 835" and N6" being normally spring biased into engagement with their stationary contacts.

The limit switch for restricting the rotation of the shaft 5 to any desired number of revolutions in either direction to thus prevent injury to the cable 58 by excessive rotation of the shaft is schematically represented at Illl. The toggle switch ml thereof controls the relay circuit which includes the solenoid I25 and the toggle switch ma the relay circuit which includes the solenoid I25, the said toggle switches being actuated by the travelling nuts I05 and I08 respectively which are mounted for movement on the screw threaded shaft Hi2.

For controlling the energization of the solenoids I35 and I35 of the switch IIQ there is provided a two element push-button station I31 which may be remotely positioned and which includes a spring biased pushrbutton switch I38R for controlling what may be arbitrarily termed the righthanded rotation of the acoustical instrumentality and a spring biased push-button switch ISSL for controlling what may be arbitrarily termed the left-handed rotation of the acoustical instrumentality. The switches I38R and i381: are formed with upper and lower movable contacts I33, Nd" and HQ, I39" respectively, the lower' the switch I.

contacts the movable contact Ill is normally in spring biased engagement.

The precise mode of operation of my invention may best beappreciated by considering the various movements of translation and rotation which the acoustical instrumentality performs in use. Let it be assumed that the acoustical instrumentality is in its housed or raised position as shown in Fig.1 of the drawings and that it is desired to lower the same to an operative and extended position below the keel of the vessel. In this as sumed position the toggle switch 98 of the limit switch 86 bridges its stationary contacts thus closing a circuit from current main a, switch 98;

lamp I82G, current main HOB and thence back to the source. Lamp |32G may be green in color and advises the operator that the acoustical instrumentality is housed within the sea chest. Toggle switch 97 is spaced from its stationary contacts, when the acoustical instrumentality is housed, thus preventing closure of the circuit including the lamp I83R. The toggle switch 99 of the limit switch 88 bridges its stationary con-- tacts while the toggle switch I89 is spaced from its stationary contacts. When it is now desired to lower the acoustical instrumentality to an extended and operative position the switch |85L in the push-button station I84 is depressed resulting in the closure of a relay circuit which extends from current main I Illa through toggle switch 99, movable contact I85 of switch- I35L, lower normally closed movable contact I86" of switch |38H to relay III of switch I and thence to current main HOB. The energization of solenoid i! results in an engagement of the movable contacts I with the stationary contacts 8-4 of the switch I with attendant energization of the motor l from the current mains llfla, Hob, llllc to cause a lowering of the acoustical instrumentality. Simultaneously with the rotation of the motor IS the screw threaded shafts 88 and 89 of the limit switch 88 are set in motion and the movable nuts 90, 9|, 92 and 98 begin their travel along their respective shafts. Shortly after the motor I! is set in operation the travelling nut 9| trips its toggle switch 98 to cause'an interruption of the circuit including the lamp I82G. Also the toggle switch I08 which was spaced from its stationary contacts while the acoustical instrumentalit-y was in its uppermost and housed position is tripped by its travelling nut 98 to cause the same to bridge its stationary contacts shortly after the beginning of the motor rotation. As long as the switch. |85Lis depressed the motor l8 continues to rotate and concurrently therewith 'lay circuit including the solenoid Ill and causing deenergizationof the motor H by opening of The nut 90 may be so adjusted that shortly before the opening of the toggle switch 99 it trips the toggle switch 91 to a closed position thereby completing a circuit from the main Illa through switch 91, a lamp l-88R. and current m'ain llllb to advise the operator that asserts and is desirous of retracting the same from its extended position to a housed position within the sea chest, he depresses the switch "CH of the push-button control station I84. As a result thereof a relay circuit extending from main 8a through toggle switch I88, movable contact I86 of switch I88H, closed annular switch 59, lower the acoustical instrumentality has reached the normally closed and movable contact I88" of switch I851, and solenoid H8 of switch III to current main 8b is completed. Energization of the solenoid H9 results in the engagement of the movable contacts ill with the stationary contacts ||2h thus causing energization of the motor l5 but in a reversed direction from that previously had because of a reversed phase rotation. As the motor l5 rotates and the acoustical instrumentality moves upwardly toward its housed position, the shafts 88 and rotate therewith but in a direction which is reversed from the one previously described in the downward movement of the instrumentality. Thus the nuts 98, 9|, 92, 93 now move toward the right. Hence, shortly after the beginning of the upward movement of the instrumentality the nut .88 trips its toggle switch 91 to an open position thereby interrupting the energization of the red lamp |88R and advising the operator that the instrumentality is no longer in its extended and operative position; also the travelling nut 82 trips its toggle switch 99 to a closed position. The nut 98 is so adjusted that when the acoustical instrumentality has substantially reached its housed position within the sea chest it will operate to trip the toggle switch I00 to an open position with the result that the relay circuit previously described and including the solenoid H8 is interrupted and the motor l5 de-energized. Shortly before the arrival of the acoustical instrumentality at its housed position the travelling nut 9| trips the toggle switch 98 to its original closed position, thereby again reestablishing the lamp circuit which includes the lamp .|32G to advise the operator at the remote control panel that the acoustical instrumentality is properly housed. I

The annular switch 59, as pointed out hereinbefore, is rigidly connected to and rotates with the shaft 4 with the result that the acoustical instrumentality can only be hoisted or raised when .it has attained a predetermined angle of train.

Asshown in Fig. 4 of the drawings the brushes of the annular switch are in contact with the movable and electrically conductive portion thereof thus permitting the energization of the relay circuit which controls the hoisting of the instrumentality. Such an arrangement is desirable if the sea chest employed is rectangular in css-section, thus necessitating a proper positioning of the instrumentality prior to its entry therein. Also under certain circumstances it may be desirable to hoist the acoustical instrumentality only when it has attained a predetermined angle of train. It is to be emphasized, however, that the use of the annular switch 88 is not absolutely essential and that it may be omitted where desired, thus enabling a hoisting or raising of the acoustical instrumentality independently of its angle of train.

Suppose now that with the acoustical instrumentality in its extended position it is desired to train the same in what may be arbitrarily termed a right-handed direction at a slow speed, it being assumed that the acoustical instrumentality has been trained to its farthest position in a lefthanded direction. It will be observed that .with the acoustical instrumentality in its extended poaaaassa sition that the toggle switch ti is in engagement with its stationary contacts, thus making possible a connection of the current main IIOa with the limit switch IOI, push-button stations I31, I40 and the switches controlled thereby. In other words, energization of the motor 53 and hence training of the acoustical instrumentality is only possible when the acoustical instrumentality is in an extended and operative position. However, this arrangement is not indispensable and by severing the connection of the conductor IN to the stationary contact I45 of the limit switch 06 and reconnecting the conductor me directly to the current main Ilda it is possible to train the acoustical instrumentality in any direction regardless of its longitudinal position.

Since the switch I iI of the push-button control station M is normally in engagement with its stationary contacts M23 a relay circuit will be closed from current main I Ida through toggle switch Q'I, contacts M28, switch MI, solenoid iii and thence to current main I501). Energization of solenoid it! causes the movable contacts I28 of switch M8 to engage the stationary contacts IZls thereof thereby, as a preparatory step, selecting the low speed winding of the motor at for subsequent energization.

With the acoustical instrumentality now turned to its farthest position in a left-handed direction and it being desired to cause rotation of the acoustical instrumentality in a righthanded direction, it will first be observed that the toggle switch Illl is bridging its stationary contacts and that the switch I08 is spaced from its corresponding stationary contacts. If now, the switch ISBR. of the push-button station it? is depressed a control circuit will be established which extends from current main Ilfia through toggle switch 9'5, toggle switch I07, movable contacts I38 of switch I38R, lower movable and normally closed contact I30" of switch i391 solenoid I26, and thence to current main H02). Energization of solenoid 112% results in an engagement of the movable contacts I22 with the stationary contacts I 291' of switch H9 with attendant energization of the low speed winding of motor 53 by the current mains I I M, IIM), IIfic. Rotation of the motor 53 is accompanied by rotation of the threaded shaft I02 oi the limit switch I III along which the nuts I05, I06 travel. Shortly after the energization of the motor 53 the travelling nut I06 trips its toggle switch I08 to a closed position. The nut I05 is so adjusted that when the acoustical instrumentality been trained through the desired number of revolutions it will cause a tripping of the toggle switch III? to an open position thereby interrupting the current flow in the relay circuit including the solenoid 12c, and causing de-energization of the motor 53.

If rotation of the acoustical instrumentality in a left-handed direction is now desired, switch I39L of the push-button station Ill is depressed. A relay circuit is at once established which extends from the current main to, toggle switch SI, toggle switch I08, lower movable contact use" of switch I38R, movable contact I39, solenoid I25 and thence to the current main Heb. Energiz-ed solenoid I25 causes the movable contacts I22 to engage the stationary contacts I2 I-.-l of the switch H9 thereby reversing the phase rotation that the aforementioned excursions of rotation may be accomplished at a greater speed by depressing the switch MI of the push-button control station I40 to cause the same to engage the stationary contacts IMF. The engagement of these latter contacts by the switch Iii results in the energization of a relay circuit extending from current main IIIla toggle switch ill, switch Iti, contacts I @31 solenoid I30 and thence to the current main IIIIB. Energization of solenoid I3Il causes the movable contacts I28 of switch II t to engage the stationary contacts I26) thereof thus connecting the high speed winding of the motor 53 to the switch H9 preparatory for connection to the current mains IIfia, IIIlb, lite.

While I have shown and described alternating current motors and an alternating control circuit or system therefore for attaining the ends of my invention I do not desire to be restricted thereto since direct current motors of any suitable design and rating and direct current control systems therefore may be employed to accomplish the ends sought in an equally efiective manner.

According to the provisions of the patent statutes I have set forth the principle and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that within the scope oi the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

The invention herein described and claimed may be used and/or manufactured by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

1. An acoustical apparatus comprising in combination a partition, a member extending through said partition and movable with respect thereto,

a said member having an acoustical instrumentality at one end and a support mounted transversely of said member at the other end thereof, said acoustical instrumentality and support being secured to said member so as to be movable therewith, means for guiding said support, a plurality of chains secured to and extending cutwardly ofsaid support from both sides thereof, sprockets on each side of said support and in mesh with said chains, an electric motor mechanically coupled to all sprockets on one side of said support and, means operable to energize said motor to thereby impart translatory movement to said acoustical instrumentality.

2. An acoustical apparatus comprising in combination a partition, a member extending through said partition and movable with respect thereto. said member having an acoustical instrumentality at one end and a support mounted transverselv of said member at the other end thereof, said acoustical instrumentality and support being secured to said member so as to be movable therewith, mean for guiding said support, a plurality on each side of said support and in mesh with said chains, an electric motor mechanically coupled to all sprockets on one side of said support,

- means operable to energize said motor to thereby impart tr'anslatory movement to said acoustical instrumentality, and means for rendering said second mentioned means inoperative upon the completion of a predetermined movement of translation by said instrumentality.

3. An acoustical apparatus comprising in combination a partition, a member extending through said partition and movable with respect thereto, said member having an acoustical instrumentality atone end and a support mounted transversely of said member at the other end thereof, said acoustical instrumentality and sup-. port being secured to said member so as to be movable therewith, means for guiding said support, a plurality of chains secured to and extending outwardly of said support from both sides thereof, sprockets on each side of said support and in mesh with said chains, an elecmentality, and means mechanically coupled to said motor for rendering .said second mentioned means inoperative upon the completion of a predetermined movement of translation by said instrumentality.

4. An acoustical apparatus comprising in combination a chamber open at one end, a member extending through the end wall of said chamber and movable with respect thereto, said member having an acoustical instrumentality at one end and a support mounted transversely of said member at the other end thereof, said acoustical instrumentality and support being secured to said member so as to be movable therewith, a travelling bearing interposed between and incontact with said member and the side wall of said chamber, means for guiding said support, a plurality of chains secured to and extending outwardly of said support from both sides thereof, sprockets on each side of said support and in mesh with said chains, an electric motor mechanically coupled to all sprockets on one side of said support and means operable to energize said motor to cause the same to extend or retract the said instrumentality from or to within said chamber.

An acoustical apparatus comprising in combination a chamber open at one end, amember extending through the end wall of said chamber and movable with respect thereto, said member having an acoustical instrumentality at one end and a support mounted transversely of said member at the other end thereof, said acoustical instrumentality and support being secured to said member so as to be movable therewith, a travelling bearing interposed between and in contact with said member and the side wall of said chamber, means forguiding said support, a. plurality of chains secured to and extending outwardly-of said support from both sides thereof, sprockets on each side of electric motor mechanically coupled to all sprockets on one side of said support, means operable to energize said motor to cause the same to extend or retract the said instrumentality rendering said second mentioned means inoperative upon the completion of a predetermined movement of translation by said instrumentality.

6. An acoustical apparatus comprising in combination a chamber open at one end, a member extending through the end wall of said chamber and movable with respect thereto, said member having an acoustical instrumentality at one end and a support mounted transversely of I said member at the other end thereof, said acoustical instrumentality and support being se-, cured to said member so as to be movable therewith, a travelling bearing interposed between and in contact with said member and the side wall of said chamber, and means operable to impart movement to said support.

'7. An acoustical apparatus comprising in combination a chamber open at one end, a member extending through the end wall of said chamber and movable with respect thereto, said member having an acoustical instrumentality at,-

one end and a support mounted transversely of said member at. the other end thereof, said acoustical instrumentality and support being secured to said member so as to .be movable therewith, a travelling bearing interposed be.- tween and in contact with said member and the side wall of said chamber, means operable to impart movement to said support, and means for rendering said first mentioned means inoperative upon the completion of a predetermined movement of translation by said instrumenta 'ty.

8. An acoustical apparatus combination a partition, a member extending through said partition and movable with respect thereto, a support, one end of said member be-- ing rotatably mounted on said support, an

acoustical instrumentality secured to said member at the other end thereof, a gear secured to said member and in meshing engagement with a at one of a plurality of speeds and means for rendering said first mentioned means inoperative upon the completion of a predetermined 0 movement of rotation by said instrumentality.

9. An acoustical apparatus comprising in combination a partition, a member extending through said partition and movable with respect thereto,

a support, one end of said member being rotatably mounted on said support, an acoustical instru-v mentality secured to said member at the other end thereof, a gear secured to said member and in meshing engagement with a second gear rotatably mounted on said support, a shaft splined to said second mentioned gear, a plural speed electric motor mechanically coupled to said shaft, means operable to selectively energize said motor to cause the same to rotate at one of a plurality of speeds, and means mechanically coupled to said motor for rendering said first mentioned means inoperative upon the completion of a predetermined movement of rotation by said instrumentality.

10. An acoustical apparatus comprising in .said support and in mesh with said chains, an combination a partition, a member extending through said partition and movable with respect thereto, a support, one end of said member being rotatably mounted on said support, an acoustical instrumentality secured to said member at from or to within said chamber, and means for the other end thereof, an electric motor mechanicomprising in asearaa cally coupled to said member, and means operable to energize said motor to thereby impart rotary movement to said acoustical instrumentality.

ll. An acoustical apparatus comprising in combination a partition, a member extending through said partition and movable with respect thereto, a support, one end of said member being rotatably mounted on said support, an acoustical instrumentality secured to said member at the other end thereof, an electric motor mechanically coupled to said member, means operable to energize said motor to thereby impart rotary movement to said acoustical instrumentality and means for rendering said first mentioned means inoperative upon the completion of a predetermined movement of rotation by said instrumentality.

12. An acoustical apparatus comprising, in combination a partition, 2. member extending through said partition and movable with respect thereto, a support, one end of said member being rotatably mounted on said support, an acoustical instrumentality secured to said member at the other end thereof, means operable to impart rotary movement to said member, and means controlled by said member forindicating the magnitude of rotation of said instrumentality at a remote point.

13. An acoustical apparatus comprising in combination a partition, a member extending through said partition and movable with respect thereto, a support, one end of said member being rotatably mounted on said support, an acoustical instrumentality secured to said member at the other end thereof, mean operable to impart rotary movement to said member, and means for rendering said first mentioned means inopera tive upon the completion of a predetermined movement of rotation by said instrumentality.

14. An acoustical apparatus comprising in combination a chamber open at one end, a member extending through the end wall of said chamber and movable with respect thereto, a support, one end of said member being rotatably mounted on said support, an acoustical instrumentality secured to said member at the other end thereof,

. a travelling bearing interposed between and in contact with said member and the side walls of said chamber, means for guiding said support, a plurality of chains secured to said support and meshing with sprockets on each side of said supto impart either translatory or rotary movement to said instrumentality in either one of two directions, and means for rendering said second mentioned means inoperative upon the completion of predetermined movements of'tra'nslation and rotation by said instrumentality.

15. An acoustical apparatus comprising in combination a chamber open at one end, a member extending through the end wall of said chamber and movable with respect thereto, a support, one end of said member being rotatably mounted on said support, an acoustical instrumentality secured to said member at the other end thereof, a travelling bearing interposed between and in contact with said member and the side walls of said chamber, means for guiding said support, a plurality of chains secured to said support and meshing with sprockets on each side of said support, an electric motor mechanically coupled to all sprockets on one side of said support, a gear secured to said member and in meshing engagement with a second gear rotatably mounted on said support, a splined shaft in sliding engagement with said second mentioned gear, a second electric motor mechanically coupled to said shait, means operable to energize said first and second mentioned motors, and means mechanically coupied to said motors for rendering said second mentioned means inoperative upon the completlon of predetermined movements of translation and rotation by said instrumentality.

16. An acoustical apparatus comprising in. combination a chamber open at one end, a member extending through the end wall of said chamber and movable with respect thereto, a support, one end of said member being rotatably mounted on said support, an acoustical instmmentality se cured to said member at the other end thereof, a. travelling bearing interposed between and in com tact with said member and the side walls of said chamber, means for guiding said support, a plus rality of chains secured to said support and meshing with sprockets on each side of said support, an electric motor mechanically coupled to all sprockets on one side of said support, a gear so cured'to said member and. in meshing engagement with a second gear rotatably mounted on said support, a splined shaft in sliding engagement with said second mentioned gear, a second electric motor mechanically coupled to said shaft and means operable to selectively energize said first and second mentioned motors.

17. An acoustical apparatus comprising in combination a partition, a member extending through said partition and movable with respect thereto, a support, one end of said member being rotat= ably mounted on said support, an acoustical instrumentality secured to said member at the other end thereof, means operable to impart translatory movement to said support and rotary movement to said member, and means for remotely indicating the position of said instrumen-= tality as well as its magnitude of rotation.

18. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart translatory and rotary movement to said instrumentality and means for remotely indicating the translatory position of said instrumentality as well as its magnitude oi rctation.

19. An acoustical apparatus comprising in com bination an acoustical instrumentality, means operable to impart translatory and rotary movement to said instrumentalitg in either oi a plurality of directions and means for rendering said first mentioned means inoperative upon the completion of predetermined movements or transla= tion and rotation by said instrumentality.

20. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart translatory and rotary movement to said instrumentality in either of a pin-- rality of directions, means for rendering said first mentioned means inoperative upon the completion of predetermined movements of translation and rotation bysaid instrumentality, and means for indicating the position of said instrumentality as well as its magnitude of rotation.

21. An acoustical apparatus comprising in combination an acoustical instrumentality, means;

operable to impart rotary movement to said instrumentality in either of a plurality of directions and means for rendering said first mentioned means inoperative upon the completion of a predetermined movement of rotation by said instrumentality.

22. An acoustical apparatus comprising in com- 1 bination an acoustical. instrumentality, means operable to impart rotary movement to said instrumentality in either of a plurality of directions and means operable to impart translatory movement to said instrumentality in either of a" plurality of directions to thus move said instrumentality to either an extended or retracted-n position, said last mentioned means being operable to move said instrumentality to a retracted position only when said instrumentality has attained a predetermined angular position.

24. An acoustical apparatus comprising in combination an acousticalyinstrumentality, means operable to impart rotary movement to said instrumentality in either of a plurality of directions and means operable to impart translatory movement to said instrumentality in either of a plurality of directions to thus move said instrumentality to either an extended or retracted position, said first mentioned means being operable to impart rotary movementto said instrumentality in either of a plurality of directions only when said instrumentality has substantially reached an extended position and said last men-- tioned means being operable to move said instrumentality to a retracted position only when the said instrumentality has attained a predetermined angular position.

25. An acoustical apparatus comprising in combination an. acoustical instrumentality, means operable to impart rotary movement to said instrumentality, and means for rendering said first mentioned means inoperative upon the completion of a predetermined movement of rotation by said instrumentality.

26. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart rotary movement of either of a plurality of speeds to said instrumentality; and means for rendering said first mentioned means inoperative upon the completion of a predetermined movement of rotation by said instrumentality.

27. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart translatory and rotary movement to said instrumentality, and means for ren-,

instrumentality and 'means for indicating the magnitute of rotation of said instrumentality.

29. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart rotary movement to said instrumentality, means for rendering said first mentioned means inoperative upon the completion of a predetermined movement of rotation by said instrumentality and means for indicating the magnitudeof rotation of said instrumentality at a remote point.

30. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart rotary movement to said instrumentality, means for renderin said first mentioned means inoperative upon the completion or a predetermined movement of rotation by said instrumentality, means for indicating the magnitude of rotation of said instrumentality and means for repeating the indication of said indicating means at a remote point.

31. An acoustical apparatus comprising incombination an acoustical instrumentality, means operable to impart rotary movement to said instrumentality, and means for indicating the magni-' tude of rotation of said instrumentality at a remote point. 1

32. An acoustical apparatus comprising in com- -.bination an acoustical instrumentality, means operable to impart rotary movement to said instrumentality, means for indicating the magnitude of rotation of said instrumentality and means for repeating the indication of said indicating means at a remote point.

33. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart translatory movement to said instrumentality, and means operable to impart rotary movement to said instrumentality only upon the completion of a predetermined movement of translation by said instrumentality.

34. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart translatory movement to said instrumentality, means operable to impart rotary movement to saidinst'rumentality only upon the completion of a predetermined movement of translation by said instrumentality, and means for rendering said first and second mentioned means inoperative upon the completion of predetermined movements oftranslation and rotation by said instrumentality.

35. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart translatory movement to said instrumentality to move-the same from a position of rest to a position outwardly thereof, and means operable to impart rotary movement to said instrumentality only when said instrumentality has substantially reached its outward position.

36. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart translatory movement to said instrumentality to move the same from a position of rest to a position outwardly thereof, means operable to impart rotary movement to said instrumentality only when said instrumentality has substantially reached its outward position, and means for rendering said first and second 'mentioned means inoperative upon the completion of predetermined movements of translation and rotation by said instrumentality.

37. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart rotary movement to said instrumentality and means operable to impart translatory movement to said instrumentality only when the same has attained a predetermined angular position.

38. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart rotary movement to said instrumen'tality, means operable to impart translatory movement to said instrumentality only when the same has attained a predetermined angular position, and nzeans for rendering said first and second mentioned means inoperative upon the completion of predetermined movements of translation and rotation by said instrumentality.

39. An acoustical apparatus comprising in combination an acoustical instrumentality, means operable to impart rotary movement to said instrumentality, means operable to impart translatory movement to said instrumentality to movethe same from a position of rest to a position inwardly thereof and being operative to accomplish the aforesaid function only when the said lnstrumentality has attained a predetermined angular position,

40. An acoustical apparatus comprising in combination an acoustical instrumentaility, means operable to impart rotary movement to said instrumentality, means operable to impart translatory movement to said instrumentality to move,

the same from a position of rest to a position inwardly thereof and being operative to accomplish the aforesaid function only when. the said instrumentality has attained a predetermined angular position, and means for rendering said first and second mentioned means inoperative upon the completion of predetermined movements 01 translation and rotation by said instrumentality.

41. An acoustical apparatus comprising in combination a partition, 9. member extending through said partition and movable with respect thereto,

said member having an acoustical instrumentality at one end and a support mounted transversely of said member at the other end thereof, said acoustical instrumentality and support being secured to said member so as to be movable therewith, translating means secured to and extending outwardly of said support from both sides thereof, revolvable means on both sides of said support for guiding said first mentioned means, and

' means operable to impart movement to said first mentioned means whereby to set the support, the member and acoustical instrumentality into motion.

42. An acoustical apparatus comprising in combination a partition, a member extending through of, a sprocket on each side of said support and in mesh wlthsaid chain, and means operable to impart movement to one of said sprockets whereby to set the chain, the support, the member and acoustical instrumentality into motion.

43. An acoustical apparatus comprising in combination a partition, a member extending through said partition and movable with respect thereto, said member having an acoustical instrumentality at one end and a support mounted transversely of said member at the other end thereof, said acoustical instrumentality and said support being secured to said member so as to be movable therewith, means for guiding said support, a plurality of chains secured to and extending outwardly of said support from both sides thereof, sprockets on each side of said support and in mesh with said chains, and means operable to impart movement to all sprockets on one side of said support whereby to set the chains, the support, the member and'acoustical instrumentality into motion. W

44. An acoustical apparatus comprising in combination a partition, 8. member extending through said partition and movable with respect thereto, said member having an acoustical instrumentality at one end and a support mounted transversely of said member at the other end thereof, said acoustical instrumentality and said support being secured to said member so as to be movable therewith, means for guiding said support, a plurality of chains secured to and extending outwardly of said support from both sides thereof, sprockets on each side of said support and in mesh with said chains, means operable to impart movement to all sprockets on one side of said support whereby to set the chains, the support, the member and acoustical instrumentality into motion, and means for rendering said second mentioned means inoperative upon the completion of a predetermined movement of translation by said instrumentallty.

PHILIP T. RUSSELL. 

